Since conventional suspension cables of bridges have smooth outer sheathings and the cable pitch is steep, conventional cars for traveling on such cables cannot be propelled by the tread rollers or bearing pulleys of the cars which engage one or more cables. The car is, therefore, traditionally provided with a cable winch. The cable winch includes a traction cable attached to the pylon on the bridge. This is particularly disadvantageous since workers must first climb the pylon while encumbered, and then fasten one end of a cable to this pylon.